Controlling flow downhole in an oil and gas well is an established practice in the oil and gas industry. It is well known to run in shifting tools downhole to open and close sleeve valves installed deep within casing in the wellbore to control the flow of fluids to and from the wellbore and formation. Similarly, it is known to distribute steam along steam injection wells in Steam Assisted Gravity Drainage operations (SAGD), by pre-determining distribution, or manually shifting valves.
Common amongst these operations is a desire for flexibility in the timing and where to control such flows.
In hydraulic fracturing operations, described in more detail below, downhole tools, such as a bottom hole assembly (BHA), are typically run downhole on coiled tubing to control sleeves in a completion string of casing and can also be used to control stimulation fluids through open sleeves.
In hydrocarbon operations, plug-and-perforation (plug and perf) systems require wireline services/coiled tubing (CT) services to run in hole (RIH) a select-fire perforating gun with one or more bridge plugs so as to plug and perforate sections of cased horizontal wells for subsequent stimulation operations such as hydraulic fracturing. This is a time consuming process, oft-times requiring the alternate suspension of a frac operation of a previous perforation to move uphole and perforate subsequent sections of the well. This process is then repeated for the number of stimulations desired for the horizontal wellbore. After all the stages have been completed, coiled tubing is typically RIH and used to drillout the plugs for establishing access to the toe of the wellbore. The residual, open perforations cannot be easily blocked off thereafter. Further, the initial operation of pumping the bridge plug and the perforating guns downhole against a closed lower end, bottom of the well or lower plug, particularly in horizontal completions, can be impeded by trapped fluid and pressure buildup therebelow, particularly for the first stage at the end of the well. Sometimes a costly separate first wireline trip is required to perforate the first, end stage.
Similarly, other downhole operations requiring a BHA run downhole to the bottom of the well can similarly face RIH resistance by trapped fluid below. Particularly challenging are first stage operations, lacking fluid release therebelow. Toe subs are known for relieving trapped fluid at least one time at the end of the well. Also characteristic of plug and perf operations, casing integrity pressure testing is often conducted before operations, requiring initial blockage of the cased wellbore below the test. Pressure actuated tools are available, such as the PosiFrac Toe Sleeve™, to TAM International, to enable closing of the wellbore below the sleeve for high-pressure testing thereabove without opening during the test, yet later can opened for frac operations without a need to overpressure above testing pressures. The apparatus and methodology is involved and can require staged pressure sequences, shear devices and internal metering to enable initial testing in a closed state and subsequent conversion to an open stage. Other methodology uses a plurality pf burst ports, which must accept varied pressure for actuation, sometimes at greater pressures than testing pressures, and once actuated, the reliability and volumetric flow capability being dependent upon a tricky and simultaneous opening of all ports rather than bursting of just a first port.
Turning to control of flow along a wellbore, such as hydraulic fracturing, common completion systems to open and close sleeves have used coiled tubing fit with shifting tools and dropped actuating objects such as balls. Ball drops are typically limited to a uni-direction action—usually to open sleeves in a downhole direction. Conveyed shifting tools such as those conveyed with coiled tubing are now being configured for both opening and closing of sleeves. The conveyed tools also incorporate fluid delivery systems for providing sealing and stimulation fluids, including hydraulic fracturing fluids. Wellbore access, such as with coil tubing has been, to date, a conventional and necessary expense to sleeve operations.
The sleeves themselves are often internal cylindrical sleeves having an internal profile for engagement with a like shifting tool, or an internal piston-like sleeve operated using differential pressure created by pressuring up the entire string above a packer. While those sleeves engaged by a shifting tool are being configured for more and more for shifting open and shifting closed, they are characterized by the need for a bore-restricting conveyance coiled tubing, and the infrastructure, time and expense for running the shifting tool in and out of the wellbore.
In one alternative methodology, and avoiding conveyance tubing, sleeves can be opened or closed from surface with umbilical hydraulic lines attached on the exterior of the casing and run to surface from every sleeve. The hydraulic lines are attached to a hydraulic pump/control system and they can be pumped opened or closed. Each sleeve has its control line or lines, depending on design. The fundamental problem with umbilical hydraulic line controlled sleeves is installation logistics. The cost to install the umbilical lines into a well without damaging them is also a hindrance. As horizontal wells get longer and longer the number of stages increases and after a certain point the number of umbilical control lines required to control every stage becomes too unwieldy to be practical.
In another sleeve technology, such as that disclosed in U.S. Pat. No. 9,359,859 to Metrol Technology Limited (Aberdeenshire GB), a safety valve is remotely actuated to block all flow up a production well, such as in a blowout situation. Directed to offshore scenario's, a signal is directed to tools in the production string, either though the sonar or other wireless signals. The signals are intended to be short distance transmissions, including by located a remote operated vehicle (ROV) in close proximity to the tool, or using some other wireless waveform in the 1-10 HZ range. Noise reduction is discussed for disseminating the useful signal from the background. This technology seems limited to offshore and closely spaced transmitters and receivers.
Opening and closing of sleeves has many advantages including but not limited to conventional access to the wellbore for fracing operations, for strategic closing of sleeves after fracing for wellbore healing and to mitigate flow back problems, to perform staged production testing and zonal flow control such as to block flooding.
In another aspect discussed herein, zonal flow control can be dependent upon knowledge of the flow, not from the well as a whole, but from zones or from sleeves themselves.
In another aspect, flow control into the well may be useful where incursion of water into a wellbore at a particular zone, such as from a naturally occurring aquifer or a high permeability channel, affects oil production therein. Intervention to close a sleeve valve can be taken once the zone through which the water is entering the well has been identified.
Controlling flow is also typically utilized in an effort to maximize hydrocarbon production from a particular well, stage or group of wells in a field. Reservoir flooding, using water or CO2, is one established example of techniques for maximizing hydrocarbon production using a group of wells which are fluidly connected through the reservoir. Some of the wells are used as injector wells, while other of the wells are used as production wells. The fluid, typically water or gas, is injected into the injector wells to increase reservoir energy and to sweep oil towards the production wells through which the oil is recovered. Often, maximizing reservoir flooding capability is more economical than drilling or fracturing new or existing wells.
Determination of flow patterns in the wells or groups of wells, with the objective of maximizing oil production, is conventionally determined by:                production logging a well, wherein production logging tools are run-in-hole (RIH) on the end of coiled tubing, jointed tubing or wireline for measuring, for example, rate of flow and/or whether the fluid flowing is gas, liquid, hydrocarbon, water, etc.;        injection of chemical or radioactive tracers with subsequent detection to determine where the tracers exit the particular well or group of wells; and        permanent installation of fiber optic or other sensors on the outside or the inside of the casing, with or without sleeve control lines for each sleeve valve in the casing.        
Temporary fiber optic lines can be run on wireline or coiled tubing. For example, they can be used to measure well temperature to infer inflow from various stages. Currently, the industry is predominantly using hard line fiber optic systems, where the fiber optic line is run on the exterior or interior of a casing/liner string to measure temperature and vibration at every injection point or stage in a well to infer flow. Measurement and recording of vibration and temperature over time, as well as monitoring of production changes at surface, for example an oil well in which water production increases over time, allows an operator to make judgements and decisions regarding which stage or stages are involved in the increase in water production so that an appropriate intervention can be taken. This is especially the case when the field application is a reservoir flooding application utilizing both injector wells and producing wells.
The challenge presented by conventional methods of flow detection is that, in most cases, the well must be taken off production and intervention is required, which is costly. Further, using permanently installed conventional detection and control systems is costly and logistically complicated. For example, installation of such systems is often hampered by the lack of annular space between production equipment and casing.
There is interest in the industry to develop hardware to aid in flow control, such as the injection and production of fluids from injection and/or producing wells. Further, the industry seeks to retrieve information from within the well in either a memory mode or on a real time basis from each stage or sleeve, to obtain intelligence regarding the type of fluids flowing and the location of the flow. There is great interest in retrieval of information without the need for a separate intervention to retrieve the information from the wellbore. Alternatively, there is interest in retrieval of information stored in the wellbore in memory mode at the same time as there is a need for an intervention for other reasons, such as when the existing flow is to be modified.